Photographic camera.



A.. DAWSON.

PHOTOGRAPHIC CAMERA. 'Awucmou FILED 1520.30. I9l6.

1,299,431. Patented Apr. 8,15%.

FIQZ.

3 I m zwm/r UNITED STATES PATENT onnrcn'.

ALFRED DAWSON, OF KENT, ENGLAND.

PHOTOGRAPHIG CAMERA.

1,299,431. Original application filed February 21,

To all whom it may concern:

Be it known that I, ALFRED DAWSON, a subject of the King of Great Britain and Ireland, residing in Kent, England, have invented new and useful Improvements in Photographic Cameras, of which the following is a specification.

This invention which is a division from the subject matter of Patent No. 1214016, dated January 30, 1917, relates to cameras employed in the art of photography and more particularly to cameras which areused in the production of natural color negatives, and wherein a plurality of sensitive surfaces are exposed simultaneously in the camera through one lens.

The invention consists in providing the camera with plane-parallel light-transmitting elements whose planes bisect one another on the optical axis of the lens, so that the light passing through the lens-is either transmitted or reflected onto the various sensitizedplates or surfaces.-

The invention can be more readily understood by reference to the accompanying drawings, in which Figure 1 is a section through a camera provided with three pockets for holding negative plates. 1

Fig. 2 is an enlarged detail taken at the point of bisection of the light-transmitting or reflecting elements.

The frame 0; of the camera is fitted with three pockets b, c, and (Z, in which are shown three negative plates 6, f and g. The lens is shown at it, through which the rays of light pass to a group of light-transmitting or reflecting elements composed of two thin plane-parallel plates "7', and 70, whose planes bisect one another at-Z onthe optical axisof the lens. The cruciform arrangement of the elements j and k may be accomplished. he outer edges of the light-transmitting ele-Q by merely slotting them together.

ments are conveniently embraced by channeled-posts m packed with elastic material a for urging them into close contact at the central bisecting joint. The said osts are secured to plates 0 disposed at t e upper and lower ends respectively of the several posts. In the drawin the lower plate s shown. The top and ottom edges of the elements fit into grooves plowed to a proper depth at the correct angle in each of the plates 0, the said elements j and is being Specification of Letters Patent.

Patented Apr. 8, 1919.

1913, Serial No. 749,877 Divided and this application filed December 30, 1916. Serial No. 139,913.

thereby snugly fitted. When the, posts, elements and plates are assembled they form a cage which can be bodily inserted in and withdrawn from the camera by a suitable construction of the body.

The rays of light in passing through the plates j and la become refracted which produces a distorted image on the sensitive surfaces. Consequently correctors p, g, and 1", having one or both surfaces curved are placed in position betweenthe respective sensitive surfaces and the light transmitting or reflecting plates j and is so as to over come this objection.

In Fig. 2 another method is shown of connecting the plates j and is, other than that already described in this case. Each element is formed in two-parts, the adjacent ends of which are prismatic in form and ground or worked to fit correctly. In some cases the ground or worked prismaticedges are blackened to prevent fogging at the centers of the sensitive plates. i'i

It is desiredto keep the elements 7' and! k as thin as compatible with the size of the camera.

' In operation, the light reaching tive surface f passes through the front portions of the plates j and k and then through their rear portions and the corrector g. Thus the light reaching the sensitive surface e is reflected from the plate 70 through the sensithe corrector p and the light reaching the 4 sensitive surface 9 is reflected from y' through the corrector 1".

By this 1nvent1on the camera can the plate be nilade much smaller than those hitherto madefforaccomplishing the same ob ect. Having thus described my invention, I claim v 1. In a photographic camera for use in the production of negatives in natural colorfi'the of a plurality of pockets for sensitive plates and two in plane-parallel light-transmitting and reflecting elements, whereof the planes bisect one another on the optical axis of the lens.

combination, with a single. objective or lens,

3. In a photographic camera! for use in the production of negatives in natural color the combination, with a single objective or lens, of a plurality of pockets for sensitive plates, two plane-parallel light-transmitting and reflecting elements whereof the planes bisect one another on the optical axis of the lens and means for correcting distortion disposed between the light-transmitting and reflecting elements and the sensitive plates.

4. In a photographic camera for use in the production of negatives in natural color the combination, with a single objective or lens, of a plurality of pockets for sensitive plates, two plane-parallel light-transmitting and reflecting elements whereof the planes bisect one another on the. optical axis of the lens and a plano-concave corrector disposed be tween the light-transmitting and reflecting elements and each sensitive plate.

5. In a photographic camera for use in'the production of negatives in natural color the combination, with the lens, of a plurality of pockets for sensitive plates, two plane-pa rallel light-transmitting and reflecting elements whereof the planes 'bisect one another in the optical aXis of the lens, channeled posts for embracing the edges of said elements, elastic packing in said posts in contact with the said elementedges and groox'ed plates for receiving the edges of the elements not embraced by said channeled posts and for securing the said channeled posts and elements in position.

6. In a photographic camera for use in the production of negatives in natural color the combination, with a single objective or lens, of a plurality of pockets for sensitive plates, two plane-parallel light-transmitting and reflecting elements whereof the planes 7. In a photographic camera for use in the production of negatives in natural color the combination, with a single objective or lens, of a plurality of pockets for sensitive plates, two plane-parallel light-transmitting and re flecting elements whereof the planes bisect one another on the optical axis of the lens, channeled posts for embracing the edges of the said elements, elastic packing in said posts in contact with said element edges,

grooved plates for receiving the edges ofsaid elements not embraced by said channeled posts and for securing the said channeled posts and elements in position and a plano-concave corrector disposed between the said light-transmitting and reflecting elements and each pocket for the sensitive plate. a

8. In a photographic camerafor use in the production of negatives in natural color the combination, with an objective or lens, of two plane-parallel light-transmitting and reflecting elements each composed of two parts whereof the meeting edges at: the point, of bisection of the planes thereof are prismatic in form and their surfaces are ground or worked to a correct fit.

ALFRED DAWSON. 

